Field of the Invention
The present invention relates to a shaft precision automatic measuring device for a motor.
Related Art
Conventionally, the shaft of a motor is inserted through front and rear bearings, and assembled in a stator. At this time, the machining precision and assembly precision of the shaft affect the shaft precision such as the rotary deflection (shaft deflection), displacement of shaft center (eccentricity) and slant of the shaft (deflection angle) due to the flexibility, etc. of the shaft. In the case of the shaft precision being low, in addition to becoming a cause of vibration and abnormal noises when the motor is assembled in a machine tool or the like, it adversely affects the machining precision of the machine tool; therefore, measurement of the shaft precision is performed after motor assembly.
Herein, various technologies have been proposed as technologies for measuring the shaft precision of a rotating body such as a motor (e.g., refer to Patent Documents 1 to 4). However, none of the technologies give sufficient consideration to automation, and the current situation is that measurement of the shaft precision in practice is performed by manual labor. More specifically, a dial gauge is attached to the motor main body or shaft, and an laborer performs measurement while rotating the shaft in this state to determine the shaft precision based on the deviation range of the measured values obtained.
Patent Document 1: Japanese Unexamined Patent Application, Publication No. H04-269601
Patent Document 2: Japanese Unexamined Patent Application, Publication No. H05-227710
Patent Document 3: Japanese Unexamined Patent Application, Publication No. H07-260425
Patent Document 4: Japanese Unexamined Patent Application, Publication No. H09-280804